"Your readiness score is 67 today." But what does that actually mean? Readiness scores have become a standard feature in fitness wearables and health apps, but the science behind them—and their limitations—often goes unexplained.
Let's look at what readiness scores measure, how they're calculated, and how to use them wisely.
What Is Readiness?
Readiness, in the context of health tracking, is an attempt to answer a simple question: Is your body ready to take on physical and mental stress today?
It's not measuring fitness. It's not measuring health. It's attempting to gauge your current capacity based on recent sleep, activity, and physiological signals.
High readiness suggests your body is recovered and prepared for demanding activity. Low readiness suggests you might benefit from rest or lighter effort.
Common Inputs to Readiness Scores
Different products use different algorithms, but most readiness scores incorporate some combination of:
Sleep Metrics
- Total sleep time
- Sleep quality and efficiency
- Time in restorative sleep stages
- Sleep consistency
Poor sleep almost always drags down readiness scores. This makes sense—sleep is the primary recovery period for both body and mind.
Heart Rate Variability (HRV)
HRV is often the most heavily weighted factor in readiness calculations. Higher HRV compared to your personal baseline suggests better autonomic balance and recovery.
Lower HRV can indicate stress, fatigue, illness, or other factors affecting your body's regulatory systems.
Resting Heart Rate
Elevated resting heart rate compared to your baseline can indicate incomplete recovery, stress, or illness. It's a simple but useful signal.
Previous Day's Activity
How hard you trained yesterday affects your readiness today. High training loads require recovery time, which is reflected in lower readiness.
Activity Balance
Some scores consider your overall training load balance—whether you've been gradually increasing, maintaining, or overdoing it over recent days and weeks.
Respiratory Rate
Changes in breathing patterns during sleep can indicate stress, illness, or other factors affecting recovery.
Body Temperature
Elevated core temperature during sleep might suggest immune response, hormonal changes, or other factors worth noting.
How Scores Are Calculated
The exact algorithms are proprietary, but the general approach is:
- Establish personal baselines for each metric
- Compare today's readings to your baselines
- Weight each factor based on its importance
- Combine into a single score (often 0-100)
The key word is "personal." Readiness scores compare you to you, not to others. A reading that's low for you might be high for someone else.
What Readiness Scores Get Right
Integration of Multiple Signals
No single metric tells the whole story. By combining sleep, HRV, heart rate, and activity data, readiness scores provide a more complete picture than any single measurement.
Personal Baselines
Using your own data as the benchmark, rather than population averages, makes the score more relevant to your individual physiology.
Trend Awareness
Good readiness algorithms consider not just today, but patterns over time. This helps distinguish between normal daily variation and meaningful changes.
Accessibility
A single number is easier to interpret than multiple data streams. For many users, this simplification makes the information actionable.
What Readiness Scores Get Wrong
False Precision
A score of 72 vs 74 is meaningless noise, not meaningful difference. The algorithms can't actually distinguish that finely. Treat scores as ranges (low, medium, high) rather than exact values.
Missing Context
Scores can't know about life factors that affect readiness: an upcoming stressful meeting, emotional distress, nutritional choices, or whether you feel motivated. Your brain has context the device doesn't.
Black Box Algorithms
Most products don't reveal exactly how scores are calculated. This makes it hard to know what's driving changes or whether the algorithm makes sense for your situation.
Potential for Anxiety
Some people check their readiness score first thing and let it dictate their mood. A low score becomes a self-fulfilling prophecy. This is using the tool wrong.
How to Use Readiness Scores
Treat as One Input, Not the Answer
Readiness scores are data to consider alongside how you feel, your schedule, your training goals, and other factors. They shouldn't dictate your day.
Look for Patterns
A single low score matters less than a pattern of declining scores over weeks. Watch trends, not individual readings.
Compare to Subjective Feel
Does your readiness score match how you feel? If the score says high but you feel terrible, trust your body. If the score says low but you feel great, you might still train—just pay attention.
Use for Adjustment, Not Cancellation
Low readiness doesn't mean do nothing. It means adjust: reduce intensity, shorten duration, or choose recovery activities instead of hard training.
Avoid Morning Obsession
Don't check your score first thing and let it determine your mood. If you find yourself doing this, consider checking later in the day or less frequently.
The Bigger Picture
Readiness scores are tools for self-awareness, not prescriptions for behavior. They work best when combined with body awareness, training knowledge, and common sense.
Used well, they can help you train smarter, recover better, and avoid pushing too hard when your body needs rest. Used poorly, they become another source of data anxiety.
The technology continues to improve, and the science behind these metrics is solid. But the numbers are always in service of the goal: a healthier, more balanced you. Don't let the score become the point.